Turbo Synchronization for Serially Concatenated CPM

In digital communication receivers, ambiguities in terms of timing and phase need to be resolved prior to data detection. In the presence of powerful error-correcting codes, which operate in low signal to noise ratios (SNR), long training sequences are needed to achieve good performance. In this contribution, we develop a new class of code-aided ambiguity resolution algorithms, which require no training sequence and achieve good performance with reasonable complexity. In particular, we focus on algorithms that compute the maximum-likelihood (ML) solution (exactly or in good approximation) with a tractable complexity, using a factor-graph representation. The complexity of the proposed algorithm is discussed, and reduced complexity variations, including stopping criteria and sequential implementation, are developed.

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“…where the last equality follows from (13). On the other hand, from (17) we have for any node v i and any j ∈ n(v i ):…”

Section: Appendix Bmentioning

confidence: 94%

Code-Aided Maximum-Likelihood Ambiguity Resolution Through Free-Energy Minimization

Herzet

Woradit

Wymeersch

et al. 2010

IEEE Trans. Signal Process.

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“…This CA approach is based on the maximum likelihood criterion, and takes benefits from the a priori soft information available from the Turbo or LDPC code structure, so that the decoder and the synchronizer are iterated jointly, and almost ideal synchronization can be obtained. In [3] the Turbo decoding structure and the maximum likelihood criterion work together, and the expectation-maximization (EM) algorithm is used for iterative synchronization, so that satisfactory timing synchronization can be obtained; Reference [4] proposes the so-called a priori probability aided (APPA) algorithm, which embeds the synchronization into the iterative decoding structure of Turbo codes, and uses the extrinsic information to get the almost ideal estimation; the maximum mean square soft-output (M 2 S 2 O) synchronization algorithm with an exhaustive search is proposed in [5]; Application of CA technique to CPM has been done by [6], where a turbo synchronization for serially concatenated CPM is derived.…”

Section: Introductionmentioning

confidence: 99%

Soft Timing Synchronization Algorithm for CPM Signals

Xiangchao

Xue

Zhao

et al. 2013

2013 IEEE International Conference on Green Computing and Communications and IEEE Internet of Things and IEEE Cyber, Physical A

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Continuous phase modulations (CPM) form a class of constant envelop signalling formats that are efficient both in power and bandwidth, which are suitable for satellite communications, deep space communications, mobile communications and so on. In spite of the great advantage, current CPM applications are still limited because of implementation complexity and synchronization problems. Considering the difficulty of timing synchronization for CPM signals, a general soft timing synchronization algorithm for different CPM is proposed. Using the Rimoldi decomposition of CPM signals, the soft timing synchronization algorithm is derived based on maximum likelihood criterion and the Expectation-Maximisation algorithm. The synchronizer and demodulator are iterated jointly, and the soft demodulation information provided by the CPM soft demodulator is used to aid timing estimation. Simulation results indicate that the Root Mean Square Estimation Error (RMSEE) of the soft timing synchronization is very close to the modified Cramer-Rao bound (MCRB) for general CPM signals, and the bit error rate could achieve approximate ideal performance.

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“…Trellis based techniques such as Viterbi Algorithm (VA) [6] and BCJR Algorithm [7], [8] are used in Multi-h CPM receivers. In a packetized transmission mode, it is necessary to start and terminate the phase trellis in a known state to provide uniform protection to all information bits [9].…”

Section: Introductionmentioning

confidence: 99%

Trellis termination of Multi-h CPM and the Diophantine Frobenius Problem

Saleem

Stuber

2011

2011 IEEE Wireless Communications and Networking Conference

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This paper presents a method for terminating the phase trellis in Multi-h Continuous Phase modulation (CPM). It is shown that tilted phase trellis for a Multi-h CPM signal is periodic and enables the representation of the modulator as the cascade of a periodic recursive continuous phase encoder (CPE) and a phase modulator (PM). We then pose the problem of finding the number of symbols that will terminate the tilted phase trellis, and establish a connection of its solution to the Diophantine Frobenius Problem (FP). Results are derived for the existence of a terminating sequence (TS), and bounds are established on its length in terms of the modulation parameters.

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Turbo Synchronization for Serially Concatenated CPM

Cited by 5 publications

References 17 publications

Code-Aided Maximum-Likelihood Ambiguity Resolution Through Free-Energy Minimization

Code-Aided Maximum-Likelihood Ambiguity Resolution Through Free-Energy Minimization

Soft Timing Synchronization Algorithm for CPM Signals

Trellis termination of Multi-h CPM and the Diophantine Frobenius Problem

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